1. Field of the Invention
This invention relates generally to clamping devices and, more particularly, to a power actuable swing clamp apparatus for clamping a workpiece to a table of a machine tool.
2. Discussion of the Prior Art
Swing clamp assemblies are widely used in order to selectively clamp and steadily fix a workpiece to a frame or table of a machine tool prior to the actual work operation. Swing clamps are characterized by the provision of a swinging arm which not only securely clamps the workpiece to the table in a direction along a reference axis, but also swings toward or away from the workpiece about the aforementioned reference axis in order to shift the arm to a non-interfering position to facilitate removal of the workpiece at the end of the operation.
Many of the known swing clamp assemblies are provided with a housing containing a piston which is connected to the clamping arm, and the piston is shiftable within a bore of the housing under the influence of hydraulic pressure to bring the arm into clamping engagement with the workpiece. A camming mechanism, disposed either internally or externally of the housing, turns the piston or another member interconnecting the piston and the clamping arm to thereby rotate the arm as the piston is advanced or retracted. For a number of reasons, however, known swing clamp assemblies are not entirely satisfactory.
More specifically, certain of the swing clamps according to conventional constructions have a clamping arm which swings in only a single rotative direction as the arm is moved toward a position of clamping engagement with a workpiece. Obviously, these types of clamps cannot be employed in certain situations where the arm must move in an opposite direction of rotation as the clamping position is approached. It is therefore necessary in accordance with such construction to manufacture both left-swinging and right-swinging assemblies, an inconvenience which can only add to the overall costs of manufacture and inventory.
As can be seen from a review of the various known constructions for swing clamps, in order to provide a clamp construction that may be positioned on a frame or table of a machine tool and oriented to swing in a desired direction relative to a workpiece resting on the table, numerous styles of the swing clamp are required. For example, clamps assembled to swing in a first direction may be provided on a first side of the table while clamps assembled to swing in the opposite direction are secured to the opposite side of the table, and under certain circumstances the clamps are mounted above the table surface while in other applications the clamps are secured beneath the table surface and extend upward through the surface.
Although it is possible to construct a swing clamp for any particular use or for installation into a particular type of machine, it would be desirable to provide a single construction capable of being assembled in any of a plurality of different positions relative to the table of a machine tool.